1. Field of the Invention
This invention relates to tape recording video signals.
2. Description of the Prior Art
Most broadcasting stations archive the video material which they have acquired and/or prepared for transmission. This is particularly important for news-gathering organisations where there is often a need to include archived or library material in a current news story (e.g. in an obituary story).
Traditionally, the main mass storage medium suitable for video archiving has been video tape, more recently in cassette form. However, since each tape cassette holds only about two or three hours of video material, even storing only the broadcast output of a television station requires very many cassettes. If non-broadcast material is also archived, the required number of tapes increases dramatically.
Thus, cataloguing the tapes used for archiving video material is very important. Originally, a manual cataloguing system would have been used, but of course more recently catalogues based on computer databases have been developed. In such systems, the computer allows searches to be performed against stored key words or other information characterising each tape, and then indicates to a user which tape should be accessed to retrieve the required video material.
This invention provides a digital tape recorder comprising:
means for recording video material onto video sections of a digital tape; and
means for recording digital cataloguing data associated with the video material onto cataloguing data sections longitudinally interspersed between video sections on the digital tape.
The invention recognises that in a computer database-oriented video tape cataloguing system, it is necessary to store the database entries for each tape on a rapid-access storage medium such as a computer hard disk to allow searching to be performed rapidly. However, the invention also recognises the potential problem of keeping a tape catalogue separate from the actual archived material, in that the catalogue can become corrupted or even lost through data errors or human mistakes. Also, the tape label (which previously would have been the only link between the tape contents and the record in the database catalogue) can be lost or attached to the wrong tape.
Therefore, to address these problems, a digital tape according to the present invention has cataloguing data stored digitally on the tape along with the corresponding video signals or video data.
This measure allows the contents of the tape to be identified from the digitally stored cataloguing data, even if the corresponding external database has become corrupted or the tape has been incorrectly labelled.
The skilled man may appreciate that in a helical scan tape recorder, longitudinally adjacent tracks or sections may in fact longitudinally overlap to some extent along the tape, but for the present purposes they are considered as disposed along the tape from one another.
Although the tape recorder may be (strictly speaking) a data recorder rather than a specifically designed video tape recorder, because the bulk of the data on a typical tape is video data, the tape recorder can be referred to as a video tape recorder and the resulting tapes can be referred to as video tapes.
Preferably, the digital cataloguing data stored on the tape is in a textual form which, when printed out, can be understood by a human reader. For example, ASCII characters could be encoded onto the tape to convey textual information about the tape""s contents.
Preferably, however, the cataloguing data also provides the necessary data to rebuild a computer database entry for that video material. This would allow a database to be rebuilt in the case of data loss, and would also allow a tape created on one database system (for example by one broadcasting company or studio site) to be incorporated into a database cataloguing system maintained by another broadcasting company or studio site.
This invention also provides a video archiving system comprising:
a computer database defining database entries for video material sequences;
means for generating a database entry for a current video material sequence to be archived;
a digital tape recorder as defined above, for recording one or more archived copies of the current video material sequence; and
means for generating cataloguing data to be recorded by the digital tape recorder from the database entry for the current video material sequence.
This invention also provides a digital tape on which video material and digital cataloguing data defining the video material are recorded in respective longitudinally interspersed sections of the tape.